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Intestinal Motility: Hormonal and Neurocrine Influences


The neuronal circuitry for all types of intestinal contraction is in the enteric nervous system and these contractions can be observed in the extrinsically denervated intestine. This does not mean, however, that intestinal motility is regulated solely by the enteric nervous system. Both the autonomic nervous system and the GI peptides exert important influences on intestinal motility. ACh is released by vagal efferents and some intrinsic neurons stimulate intestinal motility. Other excitatory agents include gastrin, CCK, motilin, enkephalins, and serotonin. Norepinephrine released from sympathetic efferents inhibits intestinal smooth muscle (except for the sphincters), as does epinephrine, secretin, GIP, and VIP.
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